Planter row unit furrow depth sensing apparatus and method

ABSTRACT

A row unit for a seeding machine. The row unit includes a frame, a first gauge wheel arm pivotally coupled to the frame, a first gauge wheel coupled to the first gauge wheel arm, a second gauge wheel arm pivotally coupled to the frame, a second gauge wheel coupled to the second gauge wheel arm, and a depth sensor having a potentiometer coupled to the first gauge wheel arm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/402,187, filed Sep. 30, 2016, the entire contents of which areincorporated herein by reference.

BACKGROUND

The present disclosure relates to systems and methods for plantingseeds, in particular with a row crop planter.

Various factors affect crop yields. One factor, for example, is seeddepth in a furrow. A productive crop yield is typically one that growsand emerges uniformly from the soil. Understanding planting depthprovides valuable information that may be used to generate a productivecrop yield.

SUMMARY

In one aspect, the disclosure provides a seeding machine that includes aframe, a first gauge wheel arm pivotally coupled to the frame, a firstgauge wheel coupled to the first gauge wheel arm, a second gauge wheelarm pivotally coupled to the frame, a second gauge wheel coupled to thesecond gauge wheel arm, and a depth sensor coupled to both the firstgauge wheel arm and the second gauge wheel arm, the depth sensorincluding a differential gearbox and a single potentiometer.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a gauge wheel arm pivotally coupled to the frame, agauge wheel coupled to the gauge wheel arm, and an inductive proximitysensor coupled to the frame to detect a rotational position of the gaugewheel arm.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a gauge wheel arm pivotally coupled to the frame androtatable about a pivot axis, a gauge wheel coupled to the gauge wheelarm, and a position sensor assembly to detect a rotational position ofthe gauge wheel arm about the pivot axis. The position sensor assemblyincludes both a sensing element positioned on and carried by the frameand an eccentric surface on the gauge wheel arm. The sensing elementincludes a sensing surface that faces the pivot axis.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a gauge wheel arm pivotally coupled to the frame, agauge wheel coupled to the gauge wheel arm, and a position sensorassembly to detect a rotational position of the gauge wheel arm. Theposition sensor assembly includes an eccentric surface.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a gauge wheel arm pivotally coupled to the frame androtatable about a pivot axis, a gauge wheel coupled to the gauge wheelarm, and a position sensor assembly to detect a rotational position ofthe gauge wheel arm about the pivot axis. The position sensor assemblyincludes a sensing surface and a sensed surface. When the gauge wheelarm rotates, the sensing surface remains parallel to the sensed surface.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a position sensor and a linkage coupled between thefirst gauge wheel arm and the position sensor.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a position sensor disposed between the first gauge wheelarm and the second gauge wheel arm such that the position sensor is atleast partially concealed from view between the first and second gaugewheels when viewing the seeding machine along an axis of rotation of thefirst gauge wheel.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a furrow opener coupled to the frame, a first gaugewheel arm pivotally coupled to the frame, a first gauge wheel coupled tothe first gauge wheel arm, a second gauge wheel arm pivotally coupled tothe frame, a second gauge wheel coupled to the second gauge wheel arm,and a position sensor assembly having a first position sensor to detecta rotational movement of the first gauge wheel arm, the position sensorassembly further including a second position sensor to detect wear ofthe furrow opener.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a position sensor to detect a rotational movement of thefirst gauge wheel arm, and a controller in communication with theposition sensor, wherein the position sensor outputs signalscorresponding to a position of the gauge wheel arm, and wherein thecontroller is configured to provide an alert if the first gauge wheel ismissing or if the first gauge wheel arm has remained in a same positionfor a predetermined period of time.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a first position sensor coupled to the first gauge wheelarm and a second position sensor coupled to the second gauge wheel arm.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a position sensor that includes a single sensing arraypositioned between the first gauge wheel arm and the second gauge wheelarm.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a first gauge wheel arm pivotally coupled to theframe, a first gauge wheel coupled to the first gauge wheel arm, asecond gauge wheel arm pivotally coupled to the frame, a second gaugewheel coupled to the second gauge wheel arm, and a position sensorassembly having a position sensor that includes an accelerometer coupledto the first gauge wheel arm to measure movement of the first gaugewheel arm.

In another aspect, the disclosure provides a seeding machine thatincludes a main frame, and a row unit coupled to the main frame. The rowunit has a row unit sub-frame. A gauge wheel arm is pivotally coupled tothe sub-frame, a gauge wheel is coupled to the gauge wheel arm, and aseed firmer is coupled to the sub-frame. The seeding machine alsoincludes a first position sensor coupled to at least one of thesub-frame or the gauge wheel arm. The first position sensor detects arotational position of the gauge wheel arm relative to the sub-frame.The seeding machine also includes a second position sensor coupled to atleast one of the sub-frame or the seed firmer.

In another aspect, the disclosure provides a seeding machine thatincludes a main frame, and a row unit coupled to the main frame. The rowunit has a row unit sub-frame. A gauge wheel arm is pivotally coupled tothe sub-frame, and a gauge wheel is coupled to the gauge wheel arm. Thegauge wheel has an edge. The seeding machine also includes a positionsensor coupled to the sub-frame. The position sensor detects a positionof the edge of the gauge wheel.

In another aspect, the disclosure provides a seeding machine thatincludes a main frame, and a row unit coupled to the main frame. The rowunit has a row unit sub-frame. A first gauge wheel arm is pivotallycoupled to the sub-frame, a first gauge wheel is coupled to the firstgauge wheel arm, a second gauge wheel arm is pivotally coupled to thesub-frame, and a second gauge wheel is coupled to the second gauge wheelarm. The seeding machine also includes a position sensor disposedbetween the first gauge wheel arm and the second gauge wheel arm.

In another aspect, the disclosure provides a seeding machine thatincludes a main frame, and a row unit coupled to the main frame. The rowunit has a row unit sub-frame. A gauge wheel arm is pivotally coupled tothe sub-frame, and a gauge wheel is coupled to the gauge wheel arm. Aseed firmer is pivotally coupled to the sub-frame. The seeding machinealso includes a first position sensor coupled to at least one of thesub-frame or the gauge wheel arm, a second position sensor coupled to atleast one of the sub-frame or the seed firmer, and a controller coupledto both the first position sensor and the second position sensor. Thecontroller receives signals from both the first position sensor and thesecond position sensor, and calculates a depth of a seed furrow based onthe signals from both the first position sensor and the second positionsensor.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a furrow opener coupled to the frame, and a positionsensor assembly having a position sensor that faces the furrow openerand detects wear of the furrow opener.

In another aspect, the disclosure provides a seeding machine thatincludes a frame, a ground following device coupled to the frame, afurrow following device coupled to the frame, and a position sensorassembly having a first position sensor that detects movement of theground following device and a second position sensor that detectsmovement of the furrow following device.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and adepth sensor having a potentiometer coupled to the first gauge wheelarm.

In another aspect, the disclosure provides a depth sensor. The depthsensor includes a differential gearbox having a housing, a first bevelgear disposed at least partially within the housing, a second bevel geardisposed at least partially within the housing, a third bevel geardisposed at least partially within the housing, and a fourth bevel geardisposed at least partially within the housing. The first bevel gear,the second bevel gear, the third bevel gear, and the fourth bevel gearare in mutual engagement with one another. The third bevel gear and thefourth bevel gear are coupled to the housing with a pin structure. Thedepth sensor also includes a ring gear fixed to the housing, a fifthbevel gear engaged with the ring gear, and a single potentiometer,wherein the fifth bevel gear is coupled to the single potentiometer.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a gauge wheel arm pivotallycoupled to the frame, a gauge wheel coupled to the gauge wheel arm, anda position sensor assembly configured to detect a gap corresponding to arotational position of the gauge wheel arm. The position sensor assemblyincludes a sensing target surface. The sensing target surface is atleast one of an eccentric surface or a cam surface.

In another aspect, the disclosure provides a gauge wheel arm for a rowunit. The gauge wheel arm includes a bearing section for rotatablymounting the arm to a frame for rotation about a pivot axis, an armportion extending from the bearing section, and a gauge wheel mountingportion at an end of the arm opposite the bearing section. The bearingsection has a surface. A portion of the bearing section surface definesa sensing target surface relative to the pivot axis.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor at least partiallydisposed between the first gauge wheel arm and the second gauge wheelarm such that the position sensor is at least partially concealed fromview between the first and second gauge wheels when viewing the row unitalong an axis of rotation of the first gauge wheel.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor disposed both betweenthe first gauge wheel arm and the second gauge wheel arm and under atleast a portion of the frame.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a furrow opener coupled to theframe, and a position sensor assembly having a position sensorconfigured to detect wear of the furrow opener.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a ground following devicecoupled to the frame, a furrow following device coupled to the frame,and a position sensor assembly having a first position sensor configuredto detect movement of the ground following device relative to the frame,and a second position sensor configured to detect movement of the furrowfollowing device relative to the frame.

In another aspect, the disclosure provides a row unit for a seedingmachine. The row unit includes a frame, a gauge wheel arm pivotallycoupled to the frame, a gauge wheel coupled to the gauge wheel arm, aposition sensor assembly having a position sensor configured to detect arotational position of the gauge wheel arm, and a controller coupled tothe position sensor. The controller is configured to receive a signalfrom the position sensor and to provide an alert based on the signal.

In another aspect, the disclosure provides a gauge wheel arm for a rowunit. The gauge wheel arm includes a bearing section for rotatablymounting the gauge wheel arm to a frame of the row unit for rotationabout a pivot axis, and a sensing target surface configured to bedetected by a position sensor on the row unit. The sensing surfaceincludes at least one of an eccentric surface or a cam surface.

In another aspect, the disclosure provides a gauge wheel arm for a rowunit. The gauge wheel arm includes a bearing section for rotatablymounting the arm to a frame for rotation about a pivot axis, an armportion extending from the bearing section, and a gauge wheel mountingportion at an end of the arm opposite the bearing section. The bearingsection includes a raised shoulder portion having a sensing targetsurface. The sensing surface includes a first eccentric surface and asecond eccentric surface circumferentially spaced from the firsteccentric surface.

Other aspects of the disclosure will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially schematic perspective view of a seeding machine.

FIG. 2 is a partially schematic side view of a row unit for the seedingmachine of FIG. 1, including gauge wheel arms and gauge wheels.

FIGS. 3 and 4 are perspective views of the gauge wheel arms and rotarypotentiometer position sensors coupled to each of the gauge wheel arms.

FIG. 5 is a perspective view of the gauge wheel arms and a schematicillustration of a position sensor that includes a mechanical averagingdifferential gearbox coupled to both gauge wheel arms.

FIGS. 5A-L are front, back, and perspective views of the mechanicalaveraging differential gearbox.

FIG. 6 is a perspective view of the gauge wheel arms and anover-the-shaft position sensor coupled to a pivot shaft for the gaugewheel arms.

FIGS. 7 and 8 are perspective views of the gauge wheel arms and aposition sensor that includes a sensing array and separate magnets thatare coupled to each of the gauge wheel arms.

FIG. 9 is a perspective view of the gauge wheel arms and a positionsensor that includes accelerometers coupled to the gauge wheel arms.

FIG. 10 is a side view of one of the gauge wheels, as well as a positionsensor that detects an edge of the side wheel.

FIG. 11 is a perspective view of one of the gauge wheel arms, as well asa position sensor in the form of an assembly that includes a sensingelement and a sensed surface.

FIG. 12 is a graphical representation of the output of the positionsensor of FIG. 11.

FIG. 13 is a schematic view of a sensor for measuring wear on a blade ofa seeding machine.

DETAILED DESCRIPTION

Before embodiments of the disclosure are explained in detail, it is tobe understood that the disclosure is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the accompanyingdrawings. The disclosure is capable of supporting other embodiments andof being practiced or of being carried out in various ways.

FIG. 1 illustrates a seeding machine 10 (e.g., a row crop planter). Theseeding machine 10 includes a main frame 14. A plurality of individualrow units 18 are coupled (e.g., mounted) on a rear portion of the mainframe 14, such that the row units 18 are pulled over a layer of soil 20.Alternatively, the row units 18 may be positioned forward of the frame14 and are pushed over the soil layer, or the machine may have acombination of push and pull row units 18. Seed sources, such as storagetanks 22 a-22 c, are coupled to the main frame 14, and hold seed that isdelivered, e.g., pneumatically or in any other suitable manner, to amini-hopper (not shown) associated with each row unit 18. The storagetanks 22 a-22 c are coupled to the mini-hoppers by way of conduits 26,such as hoses, and a pressurized delivery apparatus (not shown). Eachstorage tank 22 a-22 c contains the same or different varieties of seedto be planted in the soil 20. Each row unit 18 is connected to a conduit26 such that each row unit 18 is coupled to a storage tank 22 a-22 c toreceive seed. As illustrated by way of example only in FIG. 1, each rowunit 18 further includes its own sub-frame 30, to which variouscomponents (e.g., a furrow opener, a furrow closer, etc.) are mounted.

FIG. 2 illustrates an example of a row unit 118 that may be used inplace of one of the row units 18 in FIG. 1. Similar to the row unit 18,the row unit 118 is also coupled to the main frame 14. In someconstructions, a plurality of row units 118 are coupled to the mainframe 14, similar to the row units 18 in FIG. 1.

As illustrated in FIG. 2, each row unit 118 includes hoppers 122 a, 122b, which hold chemical and seed, respectively (as opposed to the rowunit 18 receiving seed from bulk storage as in the constructionillustrated in FIG. 1). The hoppers 122 a, 122 b are coupled to a rowunit sub-frame 130. Each row unit 118 also includes a gauge wheel orwheels 132 coupled to the row unit sub-frame 130. The gauge wheel 132contacts and rolls along the soil 20, and a furrow opener 134 (e.g., anopening wheel or blade or other structure having a stationary orrotating surface that contacts and moves soil away to form a furrow) iscoupled to the row unit sub-frame 130 for forming a furrow 136(illustrated schematically) in the soil 20. A seed metering device 138coupled to the row unit sub-frame 130 receives seeds from the hopper 122b and meters and dispenses the seeds into the furrow 136. A furrowcloser 140 (e.g., a closing and packing wheel or wheels or otherstructure having a stationary or rotating surface that contacts andpresses soil 20) coupled to the row unit sub-frame 130 pushes soilaround the seeds to close the furrow 136 (see FIG. 1). Each row unit 118may also include a seed firmer 144 (e.g. an angled arm as illustrated inFIG. 2, a press wheel coupled to a press wheel arm, or other structurethat firms a seed) coupled to the row unit sub-frame 130 that firms eachseed and pushes it into the open furrow 136 to ensure good seed to soilcontact before the furrow 136 is closed.

With continued reference to FIG. 2, each row unit 118 also includes atleast one depth sensor in the form of a position sensor 148 (illustratedschematically) that is used to determine a depth 154 of the furrow 136.The depth 154 is measured from a top surface 158 of the soil 20 to abottom 162 of the furrow 136, along a direction that is perpendicular tothe top surface 158 (assuming a flat, non-inclined top surface 158). Insome constructions, the depth 154 is equivalent to a distance between abottom of the gauge wheel or wheels 132 and a bottom of the furrowopener 134.

With reference to FIGS. 2-12, in some constructions one or more of theposition sensors 148 described herein detects positions of the gaugewheel arm 166 (e.g., relative to the sub-frame 130). In someconstructions the position sensor or sensors 148 detect the positions ofthe gauge wheel arm 166 by detecting rotational movement of the gaugewheel arm 166 relative to the sub-frame 130. Specifically, theillustrated row unit 118 includes two gauge wheel arms 166. The gaugewheel arms 166 are pivotally coupled to the sub-frame 130. Each gaugewheel arm 166 is coupled to one gauge wheel 132, such that rotation ofeach of the gauge wheel arms 166 changes a position of each of the gaugewheels 132 relative to the sub-frame 130 and thus relative to the opener134. As illustrated in FIG. 2, each of the gauge wheel arms 166 (onlyone being visible in FIG. 2) rotates about a pivot axis 170. When adownforce is applied to the row unit 118 (e.g., with a downforceadjustment mechanism 174) the downforce pushes the row unit 118 andconsequently the furrow opener 134 into the soil 20 to dig the furrow136. The gauge wheels 132 however continue to ride along the top surface158 of the soil 20. The depth 154 of the furrow 136 therefore depends ona position of the gauge wheels 132 relative to the furrow opener 134,and the position of the gauge wheels 132 depends on a rotationalposition of the gauge wheel arms 166 relative to the sub-frame 130.

As illustrated in FIG. 2, in some constructions signals from theposition sensor or sensors 148 are sent to a controller 178, whichcalculates the depth 154. The controller 178, when coupled to a globalpositioning system (GPS) signal processor, may generate a seed depth mapand store that map for later analysis. In some constructions a display182 is also provided (e.g., in the operator cab 12), which displays(e.g., in real time) the depth 154. The controller 178 may be positionedat various locations on seeding machine 10. For example, in someconstructions the controller 178 is positioned within the operator cab12, and signals are sent by wire or wirelessly from the position sensoror sensors 148 to the controller 178. In some constructions the positionsensor or sensors 148 themselves includes a controller 178. Otherconstructions include different locations for the controller 178.

With reference to FIG. 2, stops 186 are also provided for each gaugewheel arm 166 to limit rotation of the gauge wheel arm 166. The stops186 may be adjusted to a desired position to set the depth 154 in thefurrow 136. The position of the stops 186 may be manually adjusted or aremote adjustment assembly may be included such as shown in U.S. Pat.No. 4,413,685, the entire contents of which are incorporated herein byreference. However, during operating conditions the gauge wheel arms 132may not always be contacting the stops 186, and thus the actual depth154 may not be determined solely by knowing the position of the stops186. Additionally, the furrow opener 134 may wear during use, alteringthe actual depth 154. Thus, relying on the stops 186 alone is notsufficient to determine the actual depth 154 of the furrow 136 at anygiven time.

With reference to FIGS. 3 and 4, in some constructions one of theposition sensors 148 a is coupled to one gauge wheel arm 166, andanother position sensor 148 a is coupled to another gauge wheel arm 166,to separately detect the rotational positions of each of the gauge wheelarms 166 relative to the sub-frame 130. In the illustrated construction,each of the position sensors 148 a is a rotary potentiometer with alinkage 190 coupled to the gauge wheel arm 166. However, otherconstructions include different types of position sensors 148 a (e.g.,ultrasonic, etc.), as well as different linkages 190 than thatillustrated. The position sensors 148 a are illustrated as beingpositioned between and/or below the two gauge wheel arms 166, andcoupled to a bracket 192 of the sub-frame 130, such that the positionsensors 148 a are at least partially enclosed by the gauge wheels 132(e.g., such that the position sensors 148 a are at least partiallyconcealed from view between the gauge wheels 132 when viewing the rowunit along an axis of rotation 149 of the gauge wheel 132 or wheels 132,the axis of rotation 149 being illustrated in FIG. 5). The positionsensors 148 a are disposed below at least a portion of the sub-frame130. However, other constructions include different locations for theposition sensors 148 a. In some constructions, a controller (e.g., thecontroller 178) may integrate and average signals from both of theposition sensors 148 a.

With reference to FIG. 5, in some constructions a single position sensor148 b (illustrated schematically in FIG. 5, and in detail in FIGS.5A-5K) is used to measure rotational positions of multiple gauge wheelarms 166 at the same time, and to average the rotational positions ofthe gauge wheel arms 166. Taking an average measurement is useful, forexample, when the two gauge wheels 132 are riding over uneven orinclined surfaces, and where one gauge wheel 132 may be lifted up orraised slightly relative to the other gauge wheel 132.

With reference to FIGS. 5A-5K, in the illustrated construction theposition sensor 148 b includes a first link arm 504 and a second linkarm 508. The first link arm 504 and the second link arm 508 eachgenerally have an S-shaped or curvilinear profile, although otherconstructions include differently shaped profiles. The position sensor148 b further includes a third link arm 512 pivotally coupled to thefirst link arm 504, and a fourth link arm 516 pivotally coupled to thesecond link arm 508 with pins 520. The third link arm 512 and the fourthlink arm 516 each generally have a linear shaped profile, although otherconstructions include differently shaped profiles. The third link arm512 and the fourth link arm 516 are pivotally coupled to the gauge wheelarms 166 with pins 524 (FIG. 5D).

With continued reference to FIGS. 5A-5K, the position sensor 148 bfurther includes a differential gearbox 528 (FIG. 5D) coupled to thefirst link arm 504 and the second link arm 508. The differential gearbox528 includes an outer housing 532. As illustrated in FIGS. 5A-5C, thedifferential gearbox 528 further includes an inner housing 536 disposedwithin the outer housing 532. The inner housing 536 has a cylindricalshape, although other constructions include different shapes than thatillustrated.

A first bevel gear 540 (FIGS. 5B and 5C) is coupled to the first link504 and is disposed at least partially within the inner housing 536. Inthe illustrated construction the first bevel gear 540 is coupled to thefirst link 504 via a spline connection, although other constructionsinclude different connections. The first bevel gear 540 rotates with thefirst link 504.

A second bevel gear 544 (FIGS. 5B and 5C) is coupled to the second link508 and is disposed at least partially within the inner housing 536. Inthe illustrated construction the second bevel gear 544 is coupled to thesecond link 508 via a spline connection, although other constructionsinclude different connections. The second bevel gear 544 rotates withthe second link 508. The first bevel gear 540 and the second bevel gear544 each rotate about a common axis 546 (FIG. 5A).

A third bevel gear 548 (FIGS. 5A-5C) is disposed at least partiallywithin the inner housing 536. The third bevel gear 548 is pivotallycoupled to the inner housing 536 via a pin structure 552.

A fourth bevel gear 556 (FIGS. 5A-5C) is disposed at least partiallywithin the inner housing 536. The fourth bevel gear 556 is pivotallycoupled to the inner housing 536 with the same pin structure 552. Insome constructions the pin structure 552 also extends into the firstbevel gear 540 and the second bevel gear 544 (i.e., forms a cross-shapedbevel gear support structure, as illustrated in FIG. 5L). The thirdbevel gear 548 and the fourth bevel gear 556 each rotate about a secondcommon axis 558 (FIG. 5A) that is perpendicular to the first common axis546. In some constructions the first bevel gear 540, the second bevelgear 544, the third bevel gear 548, and the fourth bevel gear 556 areeach the same size.

With continued reference to FIGS. 5A-5C, the position sensor 148 bfurther includes a ring gear 560 that is fixed to the inner housing 536.In the illustrated construction the ring gear 560 is fixed to the innerhousing with fasteners 564, although in other constructions the ringgear 560 may be fixed in other manners, or may be integrally formed as asingle piece with the inner housing 536.

The position sensor 148 b further includes a larger, fifth bevel gear568 that engages with the ring gear 560. The fifth bevel gear 568 iscoupled to a single potentiometer 572 (illustrated schematically in FIG.5A).

As illustrated in FIGS. 5B and 5C, various other bearings, washers,and/or fasteners 576 are provided to complete the connections betweenthe components described above, and to facilitate movement of thecomponents as described further below.

During use, the row unit 18 travels along the surface of a field. If thefield contains rocks, debris, or other obstacles, one of the gaugewheels 132 may ride up and over one of the obstacles. When the one gaugewheel 132 encounters the obstacle, the gauge wheel 132 rises, causing arotation of the gauge wheel arm 166. When the gauge wheel arm 166rotates, the third link arm 512 rotates, causing rotation of the firstlink arm 504.

As illustrated in FIGS. 5A-5C, the position sensor 148 b senses anaverage position of the two gauge wheel arms 166. In particular, if thefirst link arm 504 in FIG. 5C is rotated out of the page (i.e.,counterclockwise in FIG. 5C) due to riding over the obstacle, the firstbevel gear 540 rotates counterclockwise. With the second link arm 508held stationary, the rotation of first bevel gear 540 will cause thethird bevel gear 548 to rotate and to cause rotation of the pinstructure 552. The pin structure 552 is coupled to the housing 536 suchthat the pin structure 552 and the housing 536 rotate together, causingthe ring gear 560 to rotate. This causes the fifth bevel gear 568 andshaft input to the potentiometer 572 to rotate and thus sense therotation of the first link arm 504. The pin structure 552, however, onlyrotates half as much as the first bevel gear 540 so that the input intothe potentiometer 572 is only half the gauge wheel arm 166 movement, andso that the input into the potentiometer 572 is therefore the average ofthe two gauge wheel arms 166.

If during use both the first link arm 504 and the second link arm 508are rotated out of the page together in FIG. 5C, the third bevel gear548 and the fourth bevel gear 556 will not rotate about their axes, butthe pin structure 552 will rotate the same amount as the first bevelgear 540 and the second bevel gear 544, thus rotating the housing 536and the ring gear 560.

If during use the first link arm 504 is rotated out of the page in FIG.5C while the second link arm 508 is rotated in an opposite directioninto the page, the first bevel gear 540 and the second bevel gear 544will rotate in opposite directions, causing no rotation of the pinstructure 552 and thus no change in the average position of the gaugewheel arms 166.

Other embodiments include various other gear arrangements and/or linkagearrangements other than that illustrated.

With reference to FIG. 6, in some constructions the position sensor 148c is instead an over-the-shaft sensor (illustrated schematically) in theform of an angular position sensor in contact with (e.g., fixed) to apivot shaft 198. At least one of the gage wheel arms 166 pivots aboutthe pivot shaft 198. For example, as illustrated in FIG. 6, the pivotshaft 198 extends through a bearing section 200 of one of the gaugewheel arms 166, with the pivot axis 170 extending through the pivotshaft 198. The bearing section 200 is used to rotatably mount the gaugewheel arm 166 to the frame 130 for rotation about the pivot axis 170(e.g., with the rest of the gauge wheel arm itself extending away fromthe bearing section 200 and toward the gauge wheel 132 and toward agauge wheel mounting portion at the end of the gauge wheel arm 166). Insome constructions the over-the-shaft position sensor 148 d is apotentiometer that includes a linkage or other structure coupled to thegauge wheel arm 166, although other constructions include differenttypes of sensors for measuring the angular position of the gauge wheelarm 166. In some constructions a signal relating to the rotationalposition of the gauge wheel arm 166 is sent from the position sensor 148c to the controller 178 to calculate the depth 154. In someconstructions an over-the-shaft position sensor 148 c is provided foreach gauge wheel arm 166.

With reference to FIGS. 7 and 8, in some constructions the positionsensor 148 d includes a single sensing array 202 positioned between thetwo gauge wheel arms 166 and fixed in place on the sub-frame 130. Thesensing array 202 includes for example a Hall Effect sensor(s) and/or amagneto-resistive sensor(s). The position sensor 148 d further includesa first magnet 206 coupled to (e.g., disposed on or within) one of thegauge wheel arms 166, and a second magnet 210 coupled to the other gaugewheel arm 166. In other constructions the Hall Effect sensor(s) and/ormagneto-resistive sensor(s) may be coupled to the gauge wheel arms 166,and the magnet or magnets may be positioned between the two gauge wheelarms 166 on the sub-frame 130. The sensing array 202 is illustrated asbeing positioned between the two gauge wheel arms 166, such that thesensing array 202 is at least partially enclosed by the gauge wheels132, and disposed below at least a portion of the sub-frame 130.However, other constructions include different locations for theposition sensors 148 d.

When the gauge wheel arms 166 rotate, the first magnet 206 and thesecond magnet 210 pass by the sensing array 202 (e.g., withoutcontacting the sensing array 202). The sensing array 202 detects thefirst magnet 206 and the second magnet 210, and sends one or moresignals to the controller 178. Those signals are then used to determinea rotational position of each of the gauge wheel arms 166 relative tothe sub-frame 130, and/or to average the rotational positions of thegauge wheel arms 166, and to then calculate the depth 154. In someconstructions the sensing array 202 includes a single printed circuitboard (PCB) that includes the Hall Effect sensor(s), and/ormagneto-resistive sensor(s), and/or a microcontroller (e.g., thecontroller 178 or a separate controller that communicates with thecontroller 178). In some constructions more than one magnet is coupledto one of the gauge wheel arms 166. Other sensor types may be used suchas ultrasonic, optical, etc.

With continued reference to FIGS. 7 and 8, and as described above, someconstructions of the seeding machine 10 also include a stop 186. Thestop 186 is shown in two different positions in each of FIGS. 7 and 8,for illustrative purposes, demonstrating the adjustability of the stop186.

With reference to FIG. 9, in some constructions the position sensor 148e includes at least one accelerometer 214 coupled (e.g., mounteddirectly or otherwise directly coupled) to each gauge wheel arm 166. Theaccelerometer position sensors 148 e determine the rotational positionsof the gauge wheel arms 166. In some constructions the accelerometers214 send signals (e.g., with wires or wirelessly) to the controller 178,and the controller 178 calculates the depth 154.

With reference to FIG. 10, in some constructions the position sensor 148f is a wheel edge sensor coupled to the sub-frame 130 and positioned todetect a position (e.g., height) of an edge 218 of one or more of thegauge wheels 132. The position of the edge 218 is then used to calculatethe depth 154 of the furrow 136. In some construction the wheel edgeposition sensor 148 f is an optical sensor, a capacitive sensor, anultrasonic sensor, a Hall Effect sensor, or a magneto-resistive sensor,although other constructions include different types of sensors (see forexample the sensing elements 570 in U.S. Publication No. 2017/0086349,the entire contents of which are incorporated herein by reference). Insome constructions, the edge 218 is the radially outward most edge of ametallic rim of the gauge wheel 132. In some constructions the edge 218of the gauge wheel 132 includes at least one magnet or reflector, andthe position sensor 148 f detects the magnet or reflector as it passesby the position sensor 148 f. In some constructions the Hall Effectsensor, magneto-resistive sensor, or other sensor is coupled to thegauge wheel 132, and a magnet or reflector is instead coupled to thesub-frame 130. In some constructions the controller 178 receives asignal from the position sensor 148 f relating to the edge 218 anddetermines a height of the gauge wheel 132 relative to the sub-frame130. As illustrated in FIG. 10, the wheel edge position sensor 148 f isor forms part of a vertical structure positioned adjacent the edge 218of the gauge wheel 132. In some constructions one wheel edge positionsensor 148 f is positioned adjacent each gauge wheel 132 to separatelymeasure the position of each gauge wheel 132. In some constructionssignals from the wheel edge position sensors 148 f are sent to thecontroller 178 (e.g., to be averaged together to calculate a singlemeasured depth 154). Other constructions include different shapes,sizes, and positions for the wheel edge position sensor 148 f than thatillustrated. Additionally, in the illustrated construction the edge 218is an outer edge of the gauge wheel 132. In other constructions theposition sensor 148 f may monitor other portions of the gauge wheel 132.For example, the gauge wheel 132 may include a radially inner metalportion having an outer rim, and an annular rubber or plastic tireportion coupled to the outer rim and surrounding the metal portion. Theposition sensor 148 f may detect the outer rim of the metal portion todetect wear of the metal portion. The row unit 118 may also include oneor more additional sensors to detect and monitor wear of the rubber tireportion. In some constructions the controller 178 may calibrate to takeinto account actual or anticipated wear of the rubber portion.

With reference to FIG. 11, in some constructions the position sensor 148g is an assembly that includes a sensing element 226 coupled to thesub-frame 130 (e.g., to a stationary shank of the sub-frame 130) whichdetects the distance between the sensing element 226 and a surface ofthe rotating gauge wheel arm 166. In the illustrated construction thesensing element 226 is positioned on (e.g., fixed to) and carried by thesub-frame 130. The gauge wheel arm 166 is formed with a sensing targetsurface 246 that varies non-linearly relative to the sensing element226. In some constructions, the sensing target surface 246 is eccentricrelative to the gauge wheel pivot axis 170 (i.e., the sensing targetsurface 246 is a surface having an eccentricity greater than zero). Insome constructions, the sensing target surface 246 forms a cam surface.As the gauge wheel arm 166 pivots, the distance between the sensingelement 226 and the sensing target surface 246 changes. In someembodiments the sensing target surface 246 is machined into or otherwiseintegrally forms part of a raised shoulder portion or portions 203 ofthe bearing section 200. Alternatively, the raised shoulder portion 203is omitted and the sensing target surface 246 is formed in the generallycylindrical surface of the bearing section 200. In another alternative,the sensing target surface 246 is formed on a sensor target clip (e.g.,made of ferrous and/or non-ferrous material) that is releasably coupledto the bearing section 200.

The sensing element 226 is a non-contact position sensor (e.g., aninductive proximity sensor, Hall Effect sensor, etc.) that detects arotational position of the gauge wheel arm 166. In some embodiments, thesensing element 226 is positioned so as to be at least partiallyenclosed by the gauge wheels 132, and disposed below at least a portionof the sub-frame 130. The sensing element 226 includes a sensing portion234 having at least one sensing surface (e.g., lower planar surface)that directly faces the sensing target surface 246 of the gauge wheelarm 166. As illustrated in FIG. 11, a three-dimensional projection 238of the sensing surface bounded by an outer perimeter of the sensingportion 234 (i.e., an extended region or zone of detection within whichthe sensing target surface 246 may be detected), extends normally awayfrom the sensing surface toward and perpendicular to the pivot axis 170,such that the pivot axis 170 extends through the three-dimensionalprojection 238. The dashed-line arrows illustrated in FIG. 11 representthe three-dimensional projection 238 extending away from the sensingportion 234 and passing through the bearing section 200, thus crossingpaths with the pivot axis 170. It is noted, however, that in use thesensing portion 234 detects only the sensing target surface 246 itself.Thus, the portion of the projection 238 extending past the sensingtarget surface 246 in FIG. 11 is provided only to illustrate a positionof the projection 238 relative to the pivot axis 170.

With continued reference to FIG. 11, the sensing target surface 246 issensed by the sensing element 226, which determines a proximity of thesensing target surface 246. The sensing target surface 246 is defined bya tapering thickness 242 on the raised shoulder portion 203. Asillustrated in FIG. 11, the thickness 242 a at a first portion 250 ofthe raised shoulder portion 203 is less than a thickness 242 b at asecond portion 254 of the raised shoulder portion 203. Because of thistapering thickness 242, a distance (i.e., gap) 258 between the sensingtarget surface 246 and the sensing element 226 decreases linearly as thegauge wheel arm 166 rotates counterclockwise about the pivot axis 170(i.e., as the gauge wheel arm 166 lowers). In other words, the thickness242 continuously increases moving clockwise around the sensing targetsurface 246, such that when the sensing target surface 246 rotatescounterclockwise with the gauge wheel arm 166, the distance 258continuously decreases.

In the illustrated construction, the distance 258 is directlyproportional to an angle of the gage wheel arm 166, and hence a depth ofthe furrow 136. Thus, as the distance 258 increases (representing araising of the gauge wheel arm 166), the depth of the furrow 136 alsoincreases. Conversely, as the distance 258 decreases, the depth of thefurrow 136 also decreases. FIG. 12 illustrates an example of arelationship between a measured output of the sensing element 226 andthe depth of the furrow 136, using a linear regression model.

In some constructions, the sensing target surface 246 (or a planetangent thereto) is parallel to the sensing surface (or a plane tangentthereto) of the sensing portion 234 in a least one position of the gaugewheel arm 166 (e.g., as the gauge wheel arm 166 rotates, a tangency(i.e., a line or a plane tangent to the curve) of the sensing targetsurface 246 remains parallel to the sensing surface). This parallelarrangement facilitates detection of the sensing target surface 246 bythe sensing portion 234 of the sensing element 226. In someconstructions the sensing target surface 246 (or a plane tangentthereto) is parallel to a corresponding portion of the sensing surfaceof the sensing portion 234 at all points during rotation of the gaugewheel arm 166.

One advantage of forming the gauge wheel arm 166 with the sensing targetsurface 246 (or otherwise attaching the sensing target surface 246 tothe gauge wheel arm 166) is that the sensing element 226 therebymeasures an actual gauge wheel arm 166 position (and not, for example,just the position of a gauge wheel arm stop). In some constructions, andas illustrated in FIG. 11, another sensing target surface 260 isdisposed along an opposite side of the bearing section 200, opposite agrease zurk 261. This enables the gauge wheel arm 166 to be used oneither side of the row unit 118.

With reference to FIGS. 2-12, in some constructions the positionsensor(s) 148 described above are first calibrated before anymeasurements or calculations are made, and are subsequentlyre-calibrated one or more times after extensive use of the seedingmachine 10 (e.g., once the furrow opener 134 begins to wear). Forexample, the position sensors 148 described above detect rotationalpositions of the gauge wheel arm or arms 166. However, in someconstructions to fully calculate the depth 154, those rotationalpositions must be compared with known rotational positions of the gaugewheel arms 166 when the depth 154 of the furrow 136 is considered zero.To determine those known rotational positions, the row unit 118 mayfirst be placed for example on a flat, hard surface (e.g., concrete),such that a bottom of the furrow opener 134 and bottoms of the gaugewheels 132 are all in contact with the concrete. The rotationalpositions of the gauge wheel arms 166 are then measured. Thosemeasurements may then be used by the controller 178 to determine changesin the rotational positions of the gauge wheels 132 during operation,and to thereby fully calculate the depth 154. By using the positionsensor or sensors 148, the actual depth 154 may be determined on acontinuous basis.

In addition to sensing the depth 154, the position sensor 148 outputsignals may also or alternatively be used as a diagnostic tool. Forexample, if a gauge wheel 132 remains in the same position for anextended (e.g., predetermined) period of time, this may indicate amalfunction on the row unit 118 that is holding the gauge wheel 132 inplace. Likewise, loss of a gauge wheel 132 (i.e., a missing gauge wheel132 that is no longer coupled to the gauge wheel arm 166) may beindicated by the signals. While this is rare, loss of a gauge wheel 132may otherwise be undetected for a long time. Thus, use of the positionsensors 148 helps to alert the operator of a lost gauge wheel 132 (e.g.,via an alert sent from the controller 178 upon receipt of the signalsfrom the position sensor 148). Additionally, in some constructions theposition sensor 148 may provide output signals that are used to indicateif the first gauge wheel arm 166 is out of an expected position by apredetermined magnitude or for a predetermined duration of time (e.g.,the gauge wheel arm 166 is stuck and remaining in the same position) oris oscillating greater than a predetermined frequency about its pivotaxis 170 (e.g., indicating further downforce may be needed to control orstabilize the gauge wheel arm 166), or if a differential between the twogauge wheels arms 166 is equal to or greater than a predeterminedthreshold and/or equal to or greater than a predetermined threshold fora predetermined amount of time (e.g., indicating that the two gaugewheel arms 166 are concurrently at different rotational positions fortoo great of a period of time).

With reference to FIG. 2, in some constructions the row unit 118includes at least one further position sensor 150 positioned on oradjacent the seed firmer 144. The further position sensor 150 measures arotational position of the seed firmer 144 relative to the sub-frame 130(e.g., by detecting rotational movement of the seed firmer 144 relativeto the sub-frame 130). For example, in the illustrated construction theseed firmer 144 is rigid is coupled to the sub-frame 130 via a four-barpivoting linkage 222 (see for example U.S. Patent Publication No.2017/0086360 and U.S. Patent Publication No. 2017/0086362, both of whichare incorporated in their entireties herein, for examples of four-barpivoting linkages). Other seed firmers 144 may include a single rigidbar or pivoting arm, and/or may include a pressing wheel to firm theseeds. The further position sensor 150 may be a potentiometer,accelerometer, or other sensor positioned on the seed firmer 144 (e.g.,on the four-bar pivoting linkage 222). The further position sensor 150measures a rotational position of the four-bar pivoting linkage 222relative to the sub-frame 130. The further position sensor 150 may beany of a number of different types of sensors, including the types ofsensors described above in conjunction with determining the rotationalpositions of the gauge wheel arms 166. For example, the further positionsensor 150 may include a rotary potentiometer coupled to the seed firmer144 (or four-bar linkage) and to the sub-frame, or may include any otherrotary sensor coupled to a pivot point of the seed firmer 144. In someconstructions the further position sensor 150 may include anover-the-shaft type of sensor, for example if the seed firmer 144 is ofa type that pivots about a shaft. In some constructions the furtherposition sensor 150 may include a sensing array coupled to the sub-frame130 or seed firmer 144, and one or more magnets coupled to the seedfirmer 144 or sub-frame 130 to detect the rotational position of theseed firmer 144. In some constructions the further position sensor 150may include an accelerometer coupled to the seed firmer 144. In someconstructions the position sensor or sensors 148 used to detect therotational positions of the gauge wheel arms 166 are different types ofsensors than the further position sensor 150 used to detect movement ofthe seed firmer 144.

With continued reference to FIG. 2, in some constructions the signal orsignals from the further position sensor 150 are sent to the controller178, along with the signal or signals from the position sensor orsensors 148 associated with the gauge wheel arms 166. The signals fromthese various position sensors 148, 150 indicate both a rotationalposition of the seed firmer 144 relative to the sub-frame 130 and arotational position of the gauge wheels 132 relative to the frame. Usingthese signals, and assuming that the seed firmer 144 is in constantcontact with the bottom 162 of the furrow 136 (e.g., the seed firmer maybe spring biased downward into contact with the furrow bottom) and thegauge wheels 132 are in constant contact with the top surface 158 of thesoil 20 (which may be confirmed for example by a separate load sensor ona gauge wheel adjustment mechanism), the controller 178 may continuouslycalculate the depth 154 without having to calibrate or re-calibrate theposition sensors 148. This represents an actual depth measurement byanalysis of the positions of a furrow following device (e.g., the seedfirmer) and of a ground following device (e.g., the gauge wheel 132),each relative to the sub-frame 130.

With reference to FIG. 13, in some constructions the seeding machine 10includes a sensor 262 (illustrated schematically) for measuring wear onthe furrow opener 134 (or other blade on the seeding machine 10). In theillustrated construction the sensor 262 is an inductive proximity sensorcoupled to the row unit 118 or other structure, although otherconstructions include different sensors (e.g., infrared, RF, optical,capacitive, etc.). The sensor 262 faces the furrow opener 134 (i.e., ina direction into the page in FIG. 13) and a shank 266 on the sub-frame130. In other constructions the sensor 262 and/or shank 266 may belocated elsewhere (e.g., the sensor 262 may be located on the shank 266and may look out toward the furrow opener 134). In some constructionsthe sensor 262 is positioned to generally be free of dirt, moisture,etc., and is coupled to the sub-frame 130.

When the furrow opener 134 is new and unworn, the sensor 262 detects apredetermined portion of the furrow opener 134 (which is metallic in theillustrated construction). As the furrow opener 134 wears over time(e.g., to a diameter represented by the broken line 268 in FIG. 13),less of the furrow opener 134 is within a detectable region orprojection of the sensor 262. Thus, the inductive response in the sensor262 decreases with an increasing degree of furrow opener 134 wear. Insome constructions, the furrow opener 134 includes a disk blade, and thesensor 262 is a disk blade wear sensor that provides wear indicationdirectly to an operator. The sensor 262 may be mounted, for example,perpendicularly to the disk blade to detect an effective disk bladeradius (i.e., to detect a reduction in an outer portion of the diskblade after wear of the disk blade, thus representing how a radius ofthe disk blade has been reduced).

In some constructions the sensor 262 may also or alternatively be usedto monitor the quality of an outer edge of the furrow opener 134 (e.g.,to detect roundness of the furrow opener 134, dents in the edge causedby rock strikes, etc.).

In some constructions the sensor 262 is coupled to a controller (e.g.,the controller 178) to receive signals from the sensor 262. Signals fromthe sensor 262 corresponding to the level of wear of the furrow opener134 may be used by the controller to control one or more elements on theseeding machine 10 (e.g., depth adjustment mechanisms such as a supportadjustment bar and support roller like the support adjustment bar 62 andthe support roller 72 in U.S. Pat. No. 4,413,685, or other stop membersor mechanisms for setting a depth adjustment on a planting machine). Insome constructions, the sensor 262 and/or the controller 178 are coupledto a display that displays wear of the furrow opener 134 (e.g., to anoperator during use of the seeding machine 10). In some constructions,the controller 178 provides an alert if the furrow opener 134 wearsbeyond a predetermined amount.

In some constructions the seeding machine 10 includes both the sensor262, as well as one or more of the position sensors 148 described above.Similar to the sensor 262, the sensor or sensors 148 may be coupled to acontroller (e.g., the controller 178). The controller 178 monitorssignals from the sensors 262, 148 to determine both an amount of wear onthe furrow opener 134 (or other blade(s) on the seeding machine 10) aswell as movement of the gauge wheel arms 166. This information is thenused together to determine a depth of the furrow 136 and/or to controlone or more elements on the seeding machine 10. As noted above, in someconstructions one or more of the position sensors 148 are firstcalibrated before any measurements or calculations are made, and aresubsequently re-calibrated one or more times after extensive use of theseeding machine 10 (e.g., once the furrow opener 134 begins to wear). Byusing the sensor 262, such re-calibration, or normalization, followingthe initial calibration is no longer required, since the wear of thefurrow opener 134 is accounted for via the measurements from the sensor262 (i.e., the sensor 262 is used for calibration or normalization).

Without use of the sensor 262, the controller 178 may assume that thefurrow opener 134 has not worn, and that the furrow opener 134 istherefore penetrating into the furrow 134 in a consistent, identicalmanner with each use of the seeding machine 10. The controller 178 mayassume also that a particular depth of the furrow 136 is being achievedbased solely on a measured angle of the gauge wheel arms 166. With theadditional use of the sensor 262, however, the controller 10 is able totake into account and compensate for wear of the furrow opener 134.Thus, when the sensor 262 provides signals that the furrow opener 134has worn down, for example, from a first outer diameter 270 to thesecond outer diameter 268, this information may be evaluated by thecontroller 178 (e.g., used as an offset or compensation value aftermeasuring the gauge wheel arm 166 positions with the positions sensor orsensor 148) when determining the actual depth of the furrow 136.

While various different types of positions sensor are described herein,the seeding machine 10 may include any one or more of the positionssensors, or a combination thereof. Additionally, any of the sensors(e.g., position sensors) described herein may be disposed between thegauge wheel arms and/or under at least a portion of the frame, and insome constructions one or more features of the sensors (e.g., thepotentiometer, differential gearbox, sensing array, etc.) may be atleast partially concealed from view between the gauge wheel arms whenviewing the seeding machine along an axis of rotation of one of thegauge wheels. Additionally, the seeding machine 10 may use at least onecontroller, such as the controller 178, to receive signals from any ofthe position sensors described herein, and to use those signals tocontrol one or more elements on the seeding machine 10 and/or to performcalculations relating to the seeding machine 10 (e.g., corresponding tofurrow depth, positioning of components, etc.).

Following are several clauses describing various embodiments andconcepts disclosed herein:

Clause 1. A seeding machine comprising a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and adepth sensor coupled to both the first gauge wheel arm and the secondgauge wheel arm, the depth sensor including a differential gearbox and asingle potentiometer.

Clause 2. The seeding machine of clause 1, wherein the depth sensorincludes a first link coupled to the first gauge wheel arm and a secondlink coupled to the second gauge wheel arm, wherein the differentialgearbox includes a housing, a first bevel gear coupled to the first linkand disposed at least partially within the housing, a second bevel gearcoupled to the second link and disposed at least partially within thehousing, a third bevel gear coupled to and disposed within the housing,and a fourth bevel gear coupled to and disposed within the housing,wherein the first bevel gear, the second bevel gear, the third bevelgear, and the fourth bevel gear are in engagement with one another suchthat rotational movement of the first gauge wheel arm causes an equaland opposite rotational movement of the second gauge wheel arm.

Clause 3. The seeding machine of clause 2, wherein the depth sensorfurther includes a ring gear fixed to the housing, and a fifth bevelgear engaged with the ring gear, wherein the fifth bevel gear is coupledto the single potentiometer.

Clause 4. The seeding machine of clause 2, wherein the first link arm iscoupled to the first gauge wheel arm with a third link arm, and whereinthe second link arm is coupled to the second gauge wheel with a fourthlink arm.

Clause 5. The seeding machine of clause 1, wherein the differential gearbox is at least partially enclosed by the first and second gauge wheels.

Clause 6. The seeding machine of clause 1, wherein the depth sensor is afirst sensor, wherein the seeding machine includes a furrow opener and asecond sensor to detect wear of the furrow opener.

Clause 7. The seeding machine of clause 1, further comprising acontroller in communication with the depth sensor, wherein the depthsensor outputs signals corresponding to positions of the gauge wheelarms, and wherein the controller is configured to provide an alert ifone of the gauge wheel arms is missing or if one of the gauge wheel armshas remained in a same position for a predetermined period of time.

Clause 8. A seeding machine comprising a frame, a gauge wheel armpivotally coupled to the frame, a gauge wheel coupled to the gauge wheelarm, and a position sensor assembly configured to detect a rotationalposition of the gauge wheel arm, the position sensor assembly includingan eccentric surface.

Clause 9. The seeding machine of clause 8, wherein the position sensorassembly includes an inductive proximity sensor positioned on andcarried by the frame, the inductive proximity sensor configured todetect a proximity of the eccentric surface.

Clause 10. The seeding machine of clause 9, wherein the gauge wheel armincludes a bearing section having a raised shoulder portion with atapered thickness, the raised shoulder portion defining the eccentricsurface such that as the gauge wheel arm pivots relative to the frame, adistance between the inductive proximity sensor and the eccentricsurface changes.

Clause 11. The seeding machine of clause 9, wherein a distance betweenthe eccentric surface and the inductive proximity sensor changes as thegauge wheel arm is rotated.

Clause 12. The seeding machine of clause 8, wherein a ferrous clip isreleasably coupled to an end of the gauge wheel arm, the ferrous clipincluding the eccentric surface.

Clause 13. The seeding machine of clause 8, wherein the gauge wheel armis rotatable about a pivot axis, wherein the position sensor assemblyincludes a sensing element having a sensing surface that faces the pivotaxis.

Clause 14. The seeding machine of clause 13, wherein as the gauge wheelarm rotates, the eccentric surface remains parallel to the sensingsurface.

Clause 15. The seeding machine of clause 13, wherein the sensing elementis an inductive proximity sensor.

Clause 16. The seeding machine of clause 8, wherein the seeding machineincludes a furrow opener, and wherein the position sensor assemblyincludes a sensor to detect wear of the furrow opener.

Clause 17. The seeding machine of clause 8, further comprising acontroller in communication with the position sensor assembly, whereinthe position sensor assembly provides outputs signals corresponding to aposition of the gauge wheel arm, and wherein the controller isconfigured to provide an alert if the gauge wheel arm is missing or thegauge wheel arm has remained in a same position for a predeterminedperiod of time.

Clause 18. A seeding machine comprising a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor and a linkage coupledbetween the first gauge wheel arm and the position sensor.

Clause 19. The seeding machine of clause 18, wherein the position sensorincludes a potentiometer.

Clause 20. The seeding machine of clause 18, wherein the position sensorincludes a differential gearbox.

Clause 21. The seeding machine of clause 18, wherein the position sensoris a first position sensor and the linkage is a first linkage, whereinthe position sensor assembly includes a second position sensor and asecond linkage coupled between the second gauge wheel arm and the secondposition sensor.

Clause 22. The seeding machine of clause 18, wherein the linkage is afirst linkage, wherein the position sensor assembly includes a secondlinkage coupled between the second gauge wheel arm and the positionsensor.

Clause 23. The seeding machine of clause 18, wherein the position sensoris disposed below the frame.

Clause 24. The seeding machine of clause 18, wherein the seeding machineincludes a furrow opener, and wherein the position sensor assemblyincludes a sensor to detect wear of the furrow opener.

Clause 25. The seeding machine of clause 18, further comprising acontroller in communication with the position sensor, wherein theposition sensor outputs signals corresponding to a position of the firstgauge wheel arm, and wherein the controller is configured to provide analert if the first gauge wheel arm is missing or if the first gaugewheel arm has remained in a same position for a predetermined period oftime

Clause 26. A seeding machine comprising a frame. a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor disposed between thefirst gauge wheel arm and the second gauge wheel arm such that theposition sensor is at least partially concealed from view between thefirst and second gauge wheels when viewing the seeding machine along anaxis of rotation of the first gauge wheel.

Clause 27. The seeding machine of clause 26, wherein the position sensorincludes a potentiometer.

Clause 28. The seeding machine of clause 26, wherein the position sensorincludes a differential gearbox.

Clause 29. The seeding machine of clause 26, wherein the position sensorincludes an accelerometer.

Clause 30. The seeding machine of clause 26, wherein the position sensorincludes an inductive proximity sensor.

Clause 31. The seeding machine of clause 26, wherein the seeding machineincludes a furrow opener, and wherein the position sensor assemblyincludes a sensor to detect wear of the furrow opener.

Clause 32. The seeding machine of clause 26, further comprising acontroller in communication with the position sensor, wherein theposition sensor outputs signals corresponding to a position of the firstgauge wheel arm, and wherein the controller is configured to provide analert if the first gauge wheel arm is missing or if the first gaugewheel arm has remained in a same position for a predetermined period oftime.

Clause 33. A seeding machine comprising a frame, a furrow opener coupledto the frame, a first gauge wheel arm pivotally coupled to the frame, afirst gauge wheel coupled to the first gauge wheel arm, a second gaugewheel arm pivotally coupled to the frame, a second gauge wheel coupledto the second gauge wheel arm, and a position sensor assembly having afirst position sensor to detect a rotational movement of the first gaugewheel arm, the position sensor assembly further including a secondposition sensor to detect wear of the furrow opener.

Clause 34. The seeding machine of clause 33, wherein the first positionsensor is configured to detect a rotational movement of both the firstgauge wheel arm and the second gauge wheel arm.

Clause 35. The seeding machine of clause 33, wherein the first positionsensor includes a potentiometer.

Clause 36. The seeding machine of clause 33, wherein the position sensorassembly includes a controller, wherein the controller is configured toreceive signals from both the first position sensor and the secondposition sensor, and to use the signals to determine a depth of afurrow.

Clause 37. The seeding machine of clause 36, wherein the controller isconfigured to provide an alert if one of the gauge wheel arms is missingor if one of the gauge wheel arms has remained in a same position for apredetermined period of time.

Clause 38. The seeding machine of clause 33, wherein the position sensoris at least partially enclosed by the first and second gauge wheels.

Clause 39. A seeding machine comprising a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor to detect a rotationalmovement of the first gauge wheel arm, and a controller in communicationwith the position sensor, wherein the position sensor outputs signalscorresponding to a position of the gauge wheel arm, and wherein thecontroller is configured to provide an alert if the first gauge wheel ismissing or if the first gauge wheel arm has remained in a same positionfor a predetermined period of time.

Clause 40. The seeding machine of clause 39, wherein the position sensorincludes a potentiometer.

Clause 41. The seeding machine of clause 39, wherein the position sensorincludes an inductive proximity sensor.

Clause 42. The seeding machine of clause 39, wherein the position sensorincludes an accelerometer.

Clause 43. The seeding machine of clause 39, wherein position sensor isat least partially enclosed by the first and second gauge wheels.

Clause 44. A seeding machine comprising a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor that includes a singlesensing array positioned between the first gauge wheel arm and thesecond gauge wheel arm.

Clause 45. The seeding machine of clause 44, wherein the single sensingarray includes a Hall Effect sensor.

Clause 46. The seeding machine of clause 45, wherein the position sensorincludes a first magnet coupled to the first gauge wheel arm configuredto be detected by the Hall Effect sensor.

Clause 47. The seeding machine of clause 46, wherein the position sensorincludes a second magnet coupled to the second gauge wheel armconfigured to be detected by the Hall Effect sensor.

Clause 48. The seeding machine of clause 44, wherein the single sensingarray is at least partially enclosed by the first and second gaugewheels.

Clause 49. The seeding machine of clause 44, wherein the seeding machineincludes a furrow opener, and wherein the position sensor assemblyincludes a sensor to detect wear of the furrow opener.

Clause 50. The seeding machine of clause 44, further comprising acontroller in communication with the position sensor, wherein theposition sensor outputs signals corresponding to a position of the firstgauge wheel arm, and wherein the controller is configured to provide analert if the first gauge wheel arm is missing or if the first gaugewheel arm has remained in a same position for a predetermined period oftime.

Clause 51. A seeding machine comprising a frame, a first gauge wheel armpivotally coupled to the frame, a first gauge wheel coupled to the firstgauge wheel arm, a second gauge wheel arm pivotally coupled to theframe, a second gauge wheel coupled to the second gauge wheel arm, and aposition sensor assembly having a position sensor that includes anaccelerometer coupled to the first gauge wheel arm to measure movementof the first gauge wheel arm.

Clause 52. The seeding machine of clause 51, wherein the accelerometeris mounted directly on the first gauge wheel arm.

Clause 53. The seeding machine of clause 51, wherein the accelerometeris a first accelerometer, wherein the position sensor assembly includesa second accelerometer coupled to the second gauge wheel arm to measuremovement of the second gauge wheel arm.

Clause 54. The seeding machine of clause 51, wherein the accelerometeris at least partially enclosed by the first and second gauge wheels.

Clause 55. The seeding machine of clause 51, wherein the seeding machineincludes a furrow opener, and wherein the position sensor assemblyincludes a sensor to detect wear of the furrow opener.

Clause 56. The seeding machine of clause 51, further comprising acontroller in communication with the position sensor, wherein theposition sensor outputs signals corresponding to a position of the firstgauge wheel arm, and wherein the controller is configured to provide analert if the first gauge wheel arm is missing or if the first gaugewheel arm has remained in a same position for a predetermined period oftime.

Clause 57. A seeding machine comprising a frame, a furrow opener coupledto the frame, and a position sensor assembly having a position sensorthat faces the furrow opener and detects wear of the furrow opener.

Clause 58. The seeding machine of clause 57, wherein the position sensoris an inductive proximity sensor.

Clause 59. The seeding machine of clause 57, wherein the frame includesa shank, wherein the position sensor faces both the furrow opener andthe shank.

Clause 60. The seeding machine of clause 57, wherein the frame includesa shank, wherein the position sensor is coupled to the shank and facesaway from the shank and toward the furrow opener.

Clause 61. A seeding machine comprising a frame, a ground followingdevice coupled to the frame. a furrow following device coupled to theframe, and a position sensor assembly having a first position sensorthat detects movement of the ground following device and a secondposition sensor that detects movement of the furrow following device.

Clause 62. The seeding machine of clause 61, wherein the groundfollowing device includes a gauge wheel arm pivotably coupled to theframe and the furrow following device includes a seed firmer.

Clause 63. The seeding machine of clause 62, wherein the seed firmerpivots relative to the frame at a pivot point, and wherein a rotarysensor is disposed on the pivot point.

Clause 64. The seeding machine of clause 62, wherein the seed firmer iscoupled to the frame via a four-bar pivoting linkage.

Clause 65. The seeding machine of clause 64, wherein the second positionsensor is a rotary potentiometer coupled to the four-bar pivotinglinkage and the frame.

Various features and advantages of the disclosure are set forth in thefollowing claims.

What is claimed is:
 1. A row unit for a seeding machine, the row unitcomprising: a frame; a first gauge wheel arm pivotally coupled to theframe; a first gauge wheel coupled to the first gauge wheel arm; asecond gauge wheel arm pivotally coupled to the frame; a second gaugewheel coupled to the second gauge wheel arm; and a depth sensor having apotentiometer coupled to the first gauge wheel arm.
 2. The row unit ofclaim 1, wherein the depth sensor includes a differential gearboxcoupled to the potentiometer, and wherein the potentiometer is a singlepotentiometer coupled to both the first gauge wheel arm and the secondgauge wheel arm.
 3. The row unit of claim 2, wherein the depth sensorincludes a first link coupled to the first gauge wheel arm and a secondlink coupled to the second gauge wheel arm, wherein the differentialgearbox includes a housing, a first bevel gear coupled to the first linkand disposed at least partially within the housing, a second bevel gearcoupled to the second link and disposed at least partially within thehousing, a third bevel gear disposed at least partially within thehousing, and a fourth bevel gear disposed at least partially within thehousing, wherein the first bevel gear, the second bevel gear, the thirdbevel gear, and the fourth bevel gear are in mutual engagement with oneanother.
 4. The row unit of claim 3, wherein the differential gearboxincludes a pin structure that couples both the third bevel gear and thefourth bevel gear to the housing.
 5. The row unit of claim 4, whereinthe pin structure defines a cross-shaped bevel gear support structure.6. The row unit of claim 3, wherein the depth sensor further includes aring gear fixed to the housing, and a fifth bevel gear engaged with thering gear, wherein the fifth bevel gear is coupled to the singlepotentiometer.
 7. The row unit of claim 3, wherein the first link arm iscoupled to the first gauge wheel arm with a third link arm, and whereinthe second link arm is coupled to the second gauge wheel with a fourthlink arm.
 8. The row unit of claim 3, wherein the housing is an innerhousing, wherein the differential gearbox includes an outer housing, andwherein the inner housing is disposed within the outer housing.
 9. Therow unit of claim 1, wherein the potentiometer is at least partiallyconcealed from view between the first and second gauge wheels whenviewing the seeding machine along an axis of rotation of the first gaugewheel.
 10. The row unit of claim 1, wherein the depth sensor is a firstsensor, wherein the row unit includes a furrow opener and a secondsensor to detect wear of the furrow opener.
 11. The row unit of claim 1,further comprising a controller in communication with the depth sensor,wherein the depth sensor outputs signals correspond to a position of thefirst gauge wheel arm, and wherein the controller is configured toprovide an alert if the first gauge wheel arm is missing, if the firstgauge wheel arm has remained in a same position for a predeterminedperiod of time, if the first gauge wheel arm is out of an expectedposition by a predetermined magnitude or for a predetermined duration oftime or is oscillating about an axis of rotation greater than apredetermined frequency, or if a differential between the two gaugewheel arms is equal to or greater than a predetermined threshold. 12.The row unit of claim 1, wherein the depth sensor is a first sensor,wherein the row unit includes a furrow following device, and wherein therow unit includes a second sensor to detect movement of the furrowfollowing device relative to the frame.
 13. The row unit of claim 12,wherein the furrow following device includes a seed firmer.
 14. The rowunit of claim 13, wherein the seed firmer is coupled to the frame via afour-bar pivoting linkage.
 15. A depth sensor comprising: a differentialgearbox having a housing, a first bevel gear disposed at least partiallywithin the housing, a second bevel gear disposed at least partiallywithin the housing, a third bevel gear disposed at least partiallywithin the housing, and a fourth bevel gear disposed at least partiallywithin the housing, wherein the first bevel gear, the second bevel gear,the third bevel gear, and the fourth bevel gear are in mutual engagementwith one another, and wherein the third bevel gear and the fourth bevelgear are coupled to the housing with a pin structure; a ring gear fixedto the housing; a fifth bevel gear engaged with the ring gear; and asingle potentiometer, wherein the fifth bevel gear is coupled to thesingle potentiometer.
 16. The depth sensor of claim 15, wherein the pinstructure is a cross-shaped pin structure.
 17. The depth sensor of claim15, wherein the housing is an inner housing, wherein the differentialgearbox includes an outer housing, wherein the inner housing is disposedwithin the outer housing.
 18. The depth sensor of claim 15, wherein thehousing is a cylindrical housing, and wherein the ring gear is fixed tothe housing with fasteners.
 19. The depth sensor of claim 15, whereinthe first bevel gear and the second bevel gear each rotate about a firstcommon axis, and wherein the third bevel gear and the fourth bevel geareach rotate about a second common axis.
 20. The depth sensor of claim19, wherein the first common axis extends perpendicular to the secondcommon axis.
 21. The depth sensor of claim 15, wherein the first bevelgear, the second bevel gear, the third bevel gear, and the fourth bevelgear are each the same size.